We have separated membrane-polysome complexes from free membrane in lysates of bacillus subtilis and found four unique proteins in the membrane from the complexes. Efforts are under way to try to define the role of these proteins in the process of protein secretion. Polysomes from membrane-polysome complexes of B. licheniformis were allowed to complete their chains, and immunoprecipitation of the penicillinase revealed 4 forms: a 38K precursor, two 33K intermediates (with and without attached phosphatide, as revealed by 3H-glycerol incorporation), and the final secreted molecule of 29K. Diphtheria toxin was shown, in collaboration with Dr. John Murphy, to be synthesized as a larger precursor and to be secreted co-translationally.